Abstract: Integrated Paleothermometry: Reconstructing the Thermal History of Sedimentary Basins

William S. Clendenen, David R. Pevear, Christopher R. Tapscott, William R. James, Charlie S. Kim

We have integrated inorganic paleothermometers with more conventional techniques to constrain more tightly the maturity of source rocks and the timing of hydrocarbon generation, both of which help focus exploration on the most prospective areas in a basin. Predictions of maturity and yields based oil thermal modeling have relied traditionally on calibration using down-hole observations of present-day temperature and organic maturity (e.g., vitrinite reflectance). These data often are adequate in simple basins, those at maximum temperature today, or those in which yield timing is not an issue. However, other techniques are required in basins with complex geologic histories, where the timing of hydrocarbon yield is critical, or where organic maturity data are ambiguous.

Inorganic paleothermometers greatly improve our ability to constrain source-rock maturity and the timing of hydrocarbon yields in complex basins. These paleothermometers are complementary and provide information about different portions of the thermal history of a basin. The smectite-to-illite transition coupled with illite-age analysis (U.S. patent pending) constrains the heating history. In contrast, apatite fission-track analysis constrains the cooling history and can provide information about maximum temperature. These inorganic paleothermometers and the more traditional techniques have been integrated to constrain estimations of maturity, yield, and their timing in a number of basins with complex thermal histories.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994